The present invention relates generally to the structural composition of an air cleaner assembly and more particularly to an assembly which includes an intake pipe provided with switching valve means for selectively directing flow of cool air or warn air through the intake pipe.
An air cleaner assembly is known in which a switching valve is provided within an intake pipe for reducing the quantities of harmful components contained in exhaust gases. However, the intake pipe of this type of air cleaner involves considerable weight, and hence if the intake pipe is supported by means of the casing of the air cleaner in a cantilevered fashion, then the intake pipe will tend to cause resonance due to vibrations transmitted thereto from external sources. In an intake pipe having considerable weight, the vibration is then transmitted to the body of the casing of the cleaner, thereby creating noise from the intake pipe and the casing which involves a large surface area.
Additionally, major sources of noise caused by vibration may include a connecting portion which extends between a valve body and a valve stem of the switching valve which is mounted within the intake pipe. A further source of such noise from vibration is the contacting portion between the valve body and the intake pipe. Thus, there results a considerable degree of wear in the aforementioned contacting portions.
In order to cope with these problems, there has been proposed a construction for an air cleaner in which the intake pipe is connected to a joint tube secured to the casing body of the cleaner by means of a rubber tube in such a manner that the rubber tube is fitted on the intake pipe at one of its ends and on the joint tube at the other end. The connecting portions of the rubber tube are tightened by means of annular bands extending therearound at the connected ends. However, such an air cleaner construction poses shortcomings in that the rubber tube is liable to be bent at its joint portion to the intake pipe so that there arises difficulty in attaching the air cleaner in position in that the rubber tube is sometimes collapsed due to vacuum or negative pressure prevailing therein. This tends to produce disadvantages in that there tends to occur an increase to the resistance of flow of intake air and that it requires a larger number of superfluous parts, such as the annular bands which must be tightened around the pipe or tube.
The present invention is intended to overcome the aforementioned disadvantages by providing an air cleaner having an intake pipe wherein the structure of the air cleaner prevents or suppresses vibration and hence reduces noise in the intake pipe while at the same time providing a device having a simplified construction.
Furthermore, the present invention is directed toward providing an cleaner having an intake pipe without requiring a rubber tube which is connected between the intake pipe and the joint tube secured to the casing of the air cleaner with the rubber tube extending in an unsupported condition. The invention avoids bending or collapse of the rubber tube and increases in resistance to the flow of intake air passing therethrough thus facilitating attachment of the cleaner.
In addition, the invention provides an air cleaner having a longer service life.